(1) Field of the Invention
This invention relates to a connector for use in connecting wire harnesses and the like, in motor vehicles and, more specifically, relates to a connector containing a front holder for fastening terminals.
(2) Description of the Related Art
In FIG. 15 there is shown a longitudinal sectional view of a conventional connector containing a front holder. In FIG. 16 there is shown a primary part of the longitudinal sectional view of the conventional connector for illustrating a problem encountered with the conventional connector.
In a body a1 of a connector housing a, there are provided a plurality of cylinders c each having a terminal receiving chamber b therein, a slit on an upper wall of an end portion c1 of the cylinder c to form a cantilever-type resilient locking arm d, and a locking projection d1 protruding toward the chamber b at a free end of the locking arm d.
As to a terminal e to be inserted into the chamber b, there is formed a locking hole e1 into which the projection d1 fits when the terminal e is fully inserted into the chamber b. When the terminal e is inserted into the chamber b (see FIG. 16), the terminal e pushes the projection d1 to deform the locking arm d, causing a detection end d2 located at the end of the locking arm d to protrude upward from the outer surface of the end portion c1 of the cylinder c. When the terminal e is fully inserted into the chamber b (see FIG. 15), the projection d1 fits in the hole e1 so that the locking arm d is lowered at the end portion c1 of the cylinder c.
A front holder f is inserted from the end of the body a1 (from left in FIG. 15) and extends along the outer surface of the end portion c1 of the cylinder c. When the locking arm d is lifted, the front holder f cannot be inserted into an end of the inserted position caused by abutting against the detection end d2. On the other hand, when the locking arm d is lowered, the front holder f can be inserted into the end of the inserted position, namely to a final inserted position.
In operation, the front holder f is partly inserted into the cylinder c up to a provisional locking position where the front holder f does not contact with the detection end d2. Then, during the insertion of the terminal e into the chamber b, the locking arm d, pushed by the terminal e, is lifted from the cylinder c. When the terminal e is fully inserted, the locking arm d is lowered, then the front holder f can be inserted up to the end of the inserted position. Upon completion of the insertion, the front holder f is locked at the final inserted position by another locking projection (not shown in the figures).
Consequently, the front holder f has one function, to detect the full insertion of the terminal e, and another function to keep the terminal e from coming off, since the front holder f restrains the locking arm d from lifting when the front holder f is inserted to the final inserted position.
In order that the front holder f detects the full insertion of the terminal e, the detection end d2 of the resilient locking arm d, which is lifted due to an incomplete insertion of the terminal e, must abut against a holder end f1 at the end of the front holder f (see FIG. 16).
Since the connector housing a and the front holder f are made of a synthetic resin and mold-shaped, there is some inevitable error in dimensions for these parts accompanied with the fabrication. Upon lifting of the locking arm d, lifted position g (see FIG. 16) of the detection end d2 is influenced by various parameters, such as the position and dimension of the terminal receiving chamber b, the diameter of the terminal e, and the dimension of the locking arm d and the projection d1 thereof.
On the other hand, internal diameter h of the front holder f has its own dimensional error accompanied with the above-mentioned fabrication. In addition, the inner diameter h must provide a clearance for allowing the front holder to be inserted with respect to the outer diameter of the end portion c1 of the cylinder c (see FIG. 16).
Therefore, when the following two situations simultaneously take place, the lifted position g of the detection end d2 can be lower than the position h corresponding to the lowest portion of the holder end f1, as illustrated in FIG. 16. The one situation is that the lifted position g becomes significantly low within the tolerance of the connector housing a and the terminal e. The another situation is that the position h becomes significantly high within the tolerance of the holder f. In the above case, the front holder f can unfavorably be inserted to the final inserted position even if the locking arm d is in a lifted state, thereby causing a problem that the incomplete insertion of the terminal e cannot be detected.
It is therefore an object of the present invention to solve the above problem.
In order to accomplish the above object, a first aspect of the present invention is to provide a connector composed in such a manner that it comprises a connector housing and a front holder, wherein the connector housing as: an insertion slot for receiving the front holder therein; a terminal receiving chamber for receiving the terminal therein; and a resilient locking arm which is resiliently deformed when pushed by the terminal and is resiliently recovered when the terminal is fully inserted into the terminal receiving chamber, the resilient locking arm having a detection end which is lowered toward the insertion slot when the resilient locking arm is resiliently deformed and is lifted toward the terminal receiving chamber when the resilient locking arm is recovered, and the front holder having a holder end facing the detection end; and a stopper which stops the front holder at a provisional locking position where the holder end is apart from the detection end and is pushed into the insertion slot when the front holder passes through the provisional locking position, the front holder, the stopper of which is released, being shifted upward so that the holder end is movable in a direction to abut against the lowered detection end of the resilient locking arm.
A second aspect of the present invention is the connector wherein the front holder has a resilient wall which slides on the insertion slot, and said stopper is provided on a sliding surface of the resilient wall. According to this structure, when the stopper is pushed into the insertion slot, the front holder is shifted upward by a resilient force produced at the resilient wall, resulting in that the holder end of the front holder is movable in a direction to abut against the lowered detection end of the resilient locking arm. Thereby, the holder end can hit the detection end so that the incomplete insertion of the terminal can be inevitably detected.
A third aspect of the present invention is the connector wherein a stopper face to abut on a stop end of the insertion slot is formed at the insertion side of the stopper. According to this structure, the front holder is securely locked at the provisional locking position.
A fourth aspect of the present invention is the connector wherein the front holder has a resilient wall which slides in the insertion slot, said stopper being provided on a sliding surface of the resilient wall, and a stopper face to abut on a stop end of the insertion slot being formed at an insertion side of the stopper.
The connector having the above structure can realize a secure locking of the terminal in the connector housing without overlooking the incomplete terminal insertion, even if there are some dimensional errors for the parts related accompanying by the fabrication thereof.